1. 獲取文本寬度

方法一：先繪制文本所在的矩形區(qū)域，再獲取矩形區(qū)域的寬度

    Rect rect = new Rect();
    mPaint.getTextBounds(text,0,text.length(), rect);
    canvas.drawRect(rect, mPaint);
? ? float textWidth1 = rect.width();
    Log.d("111","textWidth:"+textWidth1);

上述方法由于矩形邊框緊貼文字，所有沒(méi)有多余的空間。

方法二：通過(guò)Paint的measureText方法直接測(cè)量文本寬度

    float textWidth2 = mPaint.measureText(text);
    Log.d("111", "textWidth:"+textWidth2);
    canvas.drawLine(0, rect.bottom + 20, textWidth2, rect.bottom + 20, mPaint);

此方法計(jì)算出的寬度會(huì)加上開始和結(jié)尾的空間，這個(gè)空間就是文字和文字之間的空間，為了美觀而存在。如果加上下劃線會(huì)比較直觀。

方法三：計(jì)算出每個(gè)文字的寬度，最后計(jì)算總和

? ? float[] textWidths =new float[text.length()];
? ? mPaint.getTextWidths(text, textWidths);
? ? float textWidth1 =0;
? ? for(int i=0;i<textWidths.length;i++){
        textWidth1 = textWidth1 + textWidths[i];
? ? }
    Log.d("111","textWidth:"+textWidth1);

此方式計(jì)算出的寬度與方法二一樣。

    TextPaint textPaint =new TextPaint();
    textPaint.setTextSize(280);
    textPaint.setColor(Color.BLUE);
    textPaint.setStrokeWidth(8);
    textPaint.setAntiAlias(true);
    textPaint.setStyle(Paint.Style.FILL);
? ? float textWidth1 = Layout.getDesiredWidth(text,textPaint);
    Log.d("111","textWidth:"+textWidth1);

方法計(jì)算出的寬度與前兩者一致。

2. 獲取文本高度

在控件上繪制文字時(shí)，經(jīng)常要考慮到文本的中心位置，這就需要計(jì)算并獲取整個(gè)文本的寬度和高度。

看圖了解一下字體基準(zhǔn)線

上面所有的屬性都被封裝在FontMetrics類中,通過(guò)它可以獲取并計(jì)算文本的寬高

top:在一個(gè)大小確定的字體中，被當(dāng)做最高字形，基線(base)上方的最大距離。

ascent:單行文本中，在基線(base)上方被推薦的距離。

descent:單行文本中，在基線(base)下方被推薦的距離。

bottom:在一個(gè)大小確定的字體中，被當(dāng)做最低字形,基線(base)下方的最大距離。

如果我們想要計(jì)算這個(gè)文字的高度，只需要使用(descent-ascent)

通過(guò)上面的圖片對(duì)基準(zhǔn)線有了大致的了解，具體的代碼是

private void init(){
    mPaint = new Paint();
    mPaint.setColor(Color.BLUE);
    mPaint.setAntiAlias(true);
    mPaint.setStrokeWidth(8);
    mPaint.setTextSize(280);
    mPaint.setStyle(Paint.Style.FILL);
}

@Override
protected void onDraw(Canvas canvas){
? ? super.onDraw(canvas);

    canvas.translate(200,400);
    mPaint.setColor(Color.parseColor("#65A21F"));
    canvas.drawLine(-200,0, canvas.getWidth()-200,0, mPaint);
    canvas.drawLine(0,-400,0, canvas.getHeight()-400, mPaint);

    mPaint.setColor(Color.BLACK);
    mPaint.setStrokeWidth(2);
    mPaint.setStyle(Paint.Style.STROKE);
? ? Rect rect = new Rect();
    mPaint.getTextBounds(text,0,text.length(), rect);
    canvas.drawRect(rect, mPaint);
? ? float textHeight1 = rect.height();
? ? Log.d("111","textHeight:"+textHeight1);

? ? float textWidth = mPaint.measureText(text);//獲取文本的寬度
? ? Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
    mPaint.setStyle(Paint.Style.FILL);
    mPaint.setStrokeWidth(2);

    mPaint.setColor(Color.RED);
    canvas.drawLine(0, fontMetrics.ascent, mPaint.measureText(text), fontMetrics.ascent, mPaint);
    mPaint.setTextSize(50);
    canvas.drawText("ascent", textWidth, fontMetrics.ascent, mPaint);

    mPaint.setColor(Color.parseColor("#6EAD24"));
    canvas.drawLine(0, fontMetrics.bottom, textWidth, fontMetrics.bottom, mPaint);
    mPaint.setTextSize(50);
    canvas.drawText("bottom", textWidth, fontMetrics.bottom +30, mPaint);

    mPaint.setColor(Color.parseColor("#13AA9C"));
    canvas.drawLine(0, fontMetrics.descent, textWidth, fontMetrics.descent, mPaint);
    mPaint.setTextSize(50);
    canvas.drawText("descent", textWidth, fontMetrics.descent, mPaint);

    mPaint.setColor(Color.parseColor("#9C17B3"));
    canvas.drawLine(0,0, textWidth,0, mPaint);
    mPaint.setTextSize(50);
    canvas.drawText("baseline", textWidth, fontMetrics.leading, mPaint);

    mPaint.setColor(Color.parseColor("#DF3A72"));
    canvas.drawLine(0, fontMetrics.top, textWidth, fontMetrics.top, mPaint);
    mPaint.setTextSize(50);
    canvas.drawText("top", textWidth, fontMetrics.top, mPaint);

    mPaint.setTextSize(280);
    mPaint.setColor(Color.BLUE);
    mPaint.setStrokeWidth(8);
    mPaint.setStyle(Paint.Style.FILL);

    canvas.drawText(text,0,0, mPaint);}

方法一：先繪制文本所在的矩形區(qū)域，再獲取矩形區(qū)域的高度

    Rect rect = new Rect();
    mPaint.getTextBounds(text,0,text.length(), rect);
    canvas.drawRect(rect, mPaint);
? ? float textHeight1 = rect.height();
    Log.d("111","textHeight:"+textHeight1);

方法二： 通過(guò)getFontMetrics()或getFontMetricsInt()獲取測(cè)量數(shù)據(jù)

想要計(jì)算高度只需要 descent-ascent

    Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();

    float height1 = fontMetrics.descent - fontMetrics.ascent;
    Log.d("111", "文本的推薦高度："+height1);
    float height2 = fontMetrics.bottom - fontMetrics.top;
    Log.d("111", "文本的最大高度："+height2);

方法三：通過(guò)getFontSpacing實(shí)現(xiàn)文章來(lái)源地址http://www.zghlxwxcb.cn/news/detail-488954.html

    float height3 = mPaint.getFontSpacing();
    Log.d("aaa", "文本的高度："+height3);